The invention relates to a belt buckle feeder for a seat belt system of a vehicle comprising a belt buckle and comprising a spindle drive for moving the belt buckle.
Belt buckle feeders of this type for seat belt systems are known from prior art and serve for moving the belt buckle for fastening the seat belt into a comfortable position in which insertion of the plug-in tongue into the belt buckle is facilitated and after fastening the seat belt into a retaining position in which a proper retaining function of the seat belt system is ensured and/or the belt buckle does not constrain the vehicle occupant.
The spindle of the spindle drive is supported within a frame of the belt buckle feeder by means of a radial bearing radially and with the end turned away from the drive axially on the frame. The radial bearing centrically fixes the spindle within the frame of the belt buckle feeder. In most cases the radial bearing is formed of a softer annular metal element through which the spindle extends. The axial bearing is a bearing ball received in a bearing seat in the spindle, for example, which is in point contact with a corresponding bearing surface on the frame of the belt buckle feeder and there rolls off upon rotation of the spindle. This bearing is designed to exhibit tow friction and is of advantage for the reversible functions during normal driving operation.
However, it is desirable to ensure increased self-locking of the spindle drive in restraining situations caused by crash, for in the case of crash the spindle system may be excited via highly dynamic processes, e.g. by pyrotechnic tensioning of the belt system and in this way may be caused to oscillate or rotate. In especially unfavorable marginal conditions this may result in movements, in particular in a buckle head movement, which is/are not desired, however. Although the approaches existing so far are efficient, they are still expensive and complicated.